SUMMARY: Lung cancer is the second most common cancer in both men and women and accounts for about 13% of all new cancers and 21% of all cancer deaths. The American Cancer Society estimates that for 2024, about 234,580 new cases of lung cancer will be diagnosed and 125,070 patients will die of the disease. Lung cancer is the leading cause of cancer-related mortality in the United States. Non-Small Cell Lung Cancer (NSCLC) accounts for approximately 85% of all lung cancers. Of the three main subtypes of NSCLC, 30% are Squamous Cell Carcinomas (SCC), 40% are Adenocarcinomas and 10% are Large Cell Carcinomas. With changes in the cigarette composition and decline in tobacco consumption over the past several decades, Adenocarcinoma now is the most frequent histologic subtype of lung cancer.
The 5-year survival rate for patients diagnosed with lung cancer in the US is about 25%, which is a significant improvement over the past 5 years, in part due to earlier detection from lung cancer screening, reduction in smoking, advances in diagnostic and surgical procedures, as well as the introduction of new therapies. However, the 5-year survival rate remains significantly lower among communities of color at 20%. Early detection and screening remain an important unmet need, as 44% of lung cancer cases are not found until they are advanced. In the US, only 5.8% of those individuals at high risk were screened in 2021.
Approximately 50% of NSCLC patients are diagnosed at an early stage, when surgical resection is a viable treatment option. Among patients with early stage disease, 20% present with Stage I or II disease, while 30% present with Stage IIIA or IIIB disease. These patients are often treated with platinum-based neoadjuvant or adjuvant chemotherapy to eradicate micrometastatic disease and decrease the risk of recurrence. However, conventional neoadjuvant or adjuvant chemotherapy provides only a 5% absolute improvement in Overall Survival (OS) at 5 years and 45-75% of these patients develop recurrent disease. There is therefore an unmet need for this patient population.
Immunotherapy with Immune Checkpoint Inhibitors (ICIs) has revolutionized cancer care and has become one of the most effective treatment options, by improving Overall Response Rate and prolongation of survival, across multiple tumor types. These agents target Programmed cell Death protein-1 (PD-1), Programmed cell Death Ligand-1 (PD-L1), Cytotoxic T-Lymphocyte-Associated protein-4 (CTLA-4), and many other important regulators of the immune system. Checkpoint inhibitors unleash the T cells resulting in T cell proliferation, activation, and a therapeutic response. Biomarkers predicting responses to ICIs include Tumor Mutational Burden (TMB), Mismatch Repair (MMR) status, and Programmed cell Death Ligand 1 (PD‐L1) expression. Combining cytotoxic chemotherapy with a PD-1 inhibitor therapy may augment the antitumor immune response through cell-death induced increased tumor antigenicity and reduction of Treg mediated immune suppression.
Neoadjuvant Immune Checkpoint Inhibitors (ICIs) have emerged as a promising approach to enhance the surgical resectability of tumors and reduce the risk of distant relapse. Clinical trials investigating the combination of neoadjuvant ICIs with platinum-based chemotherapy (ICI-chemotherapy) in resectable NSCLC have demonstrated improvements in Event-Free Survival (EFS) and a notable increase in pathologic Complete Response (pCR), which is considered a potential surrogate for Overall Survival. Consequently, regulatory agencies such as the US FDA and the European Medicines Agency have approved neoadjuvant ICI regimens for resectable NSCLC.
Several studies have suggested greater benefits in EFS and/or pCR in patients with higher PD-L1 expression in tumor cells. As a result, the European Medicines Agency has limited the use of neoadjuvant ICI therapy in combination with platinum-based chemotherapy to NSCLC patients with tumor cell PD-L1 expression of at least 1%. Other factors potentially influencing treatment outcomes include histologic features, disease stage, and smoking history. However, uncertainties remain regarding the necessity of adjuvant postoperative ICI treatment for all patients receiving neoadjuvant ICIs with chemotherapy, and the optimal duration of preoperative treatment.
The researchers therefore conducted a systematic review and meta-analysis of Randomized Clinical Trials with neoadjuvant Immune Checkpoint Inhibitors (ICIs) plus chemotherapy (ICI-chemotherapy) with or without adjuvant ICIs, to evaluate the collective benefits of neoadjuvant ICI-chemotherapy in Event-Free Survival (EFS) and pathologic Complete Response (pCR) among early-stage NSCLC patients, and additionally investigate the impact of various clinical, pathologic, and treatment-related factors. The analysis included 8 Phase II and III Randomized Clinical Trials involving 3387 previously untreated Stage IB-IIIB NSCLC patients. It compared 2-year EFS and pCR rates between patients receiving neoadjuvant chemoimmunotherapy and those patients receiving neoadjuvant chemotherapy alone. The current analysis unlike other meta-analyses that aimed to compare different perioperative ICI-based therapies, focused on limiting heterogeneity and providing consistent and clinically helpful evidence from the subgroup analysis.
The results indicated that neoadjuvant chemoimmunotherapy significantly improved both 2-year EFS and pCR rates, compared to chemotherapy alone. Neoadjuvant chemoimmunotherapy was associated with improved 2-year EFS (HR=0.57; P<0.001) and increased pCR rate (RR=5.58; P<0.001), compared to neoadjuvant chemotherapy alone. This benefit was noted regardless of age, sex, ECOG performance status, smoking history, histologic features including tumor PD=L1 status, tumor stage, type of platinum-compound chemotherapy, number of cycles of neoadjuvant chemoimmunotherapy, or addition of adjuvant Immune Checkpoint Inhibitors. Patients with tumor cells negative for PD-L1 were at higher risk of relapse (HR=0.75), than were those with low PD-L1 (HR=0.61) or high PD-L1 (HR=0.40) and this was statistically significant (P=0.005).
In conclusion, this systemic review and meta-analysis suggests that 3 cycles of neoadjuvant platinum-based Immune Checkpoint Inhibitors plus chemotherapy for early-stage NSCLC patients leads to meaningful improvements in 2-year Event Free Survival and pathologic Complete Response. It underscores the potential of this treatment approach in enhancing outcomes for NSCLC patients and provides valuable insights into optimizing treatment strategies.
Neoadjuvant Chemo-Immunotherapy for Early-Stage Non–Small Cell Lung Cancer; A Systematic Review and Meta-Analysis. Banna GL, Hassan MA, Signori A, et al. JAMA Netw Open. 2024;7(4):e246837. doi:10.1001/jamanetworkopen.2024.6837.
